"Lockheed Martin’s F-35 is set to begin later this month a long series of operational test and evaluation flights needed to prove the program is ready to enter full-rate production in fiscal year 2020, the Joint Program Office (JPO) confirmed to Aerospace DAILY Dec. 4.

The approval ends a 16-month delay to the start of the formal initial operational test and evaluation (IOT&E) program, although the JPO launched a series of “pre-IOT&E” events earlier this year. “Formal (IOT&E) will start later this month,” a JPO spokesman said....

...Robert Behler [new DOTE], decided on Aug. 24 that formal testing wouldn’t start until Lockheed delivered a new software block dubbed “30R02.” That memo, which was disclosed by the Project on Government Oversight, said the software should be delivered by late November.

The newly approved timeline means a compressed schedule to complete IOT&E and fix any discrepancies before a planned full-rate production decision by the end of 2019...."

From the last (FY2017) DOT&E report, talking about Weapons Delivery Accuracy testing (having taken place between mid-2016 and mid-2017):

Most of the AMRAAM events were completed using work-arounds to mitigate limitations induced by outstanding deficiencies that compromised the combat capability of the weapons employment. The JPO, contractor, Services, and JOTT are assessing these weapons integration deficiencies so that problems can be addressed prior to entry into IOT&E and subsequent fielding.

Additional details are listed in the previous FY2016 DOT&E report. For example, WDA test 303, with an AMRAAM being fired at a target off-boresight, with Block 3FR5.03 software, all the way back in August 2016:

Assessment: Known issues with outdated F-35 AMRAAM Attack Model in mission systems software resulted in no shoot cues or dynamic launch zone displayed to pilot requiring the control room to provide a “shoot” call to the pilot. Initial data review indicates that there was also no post-launch timer indication to the pilot. Also, weapon quality track was erratic pre- and post-launch. More detailed analyses are pending, following data to be provided by the missile vendor.

"The F-35 Joint Strike Fighter has officially entered Initial Operational Test and Evaluation, a major program milestone that, when successfully completed, will pave the way for full-rate production of the Lightning II, which is already operating with three US services and six foreign air forces. The IOT&E effort is set to conclude in “late summer, 2019.”...

...Some elements of the evaluation started earlier this year, to save time, the Joint Program Office said. These “pre-IOT&E” evaluations included cold weather testing, weapons demonstrations, “suitability deployments” aboard ships, and “lower-threat missions.”

The new effort, under the Pentagon’s Director, Operational Test and Evaluation, will put the jet through its paces to measure “the effectiveness, suitability, lethality, survivability, and overall mission capability” of the F-35 weapons system. It will be “field tested under realistic combat conditions” and be graded on tests such as combat effectiveness, weapons accuracy, and maintainability under deployed conditions. The testing will take place on US military ranges and installations against representative threats.

It is typical that IOT&E reveals flaws and shortcomings in new systems; test pilots invariably rate new aircraft as “unsuitable” until all the bugs have been worked out.The JPO said the DOT&E will “analyze the data from the testing and prepare a report for Congress and the Secretary of Defense evaluating the results and adequacy of the test.” The F-35 “enterprise” will work to “understand and holistically address any findings.” Once that’s all done, the jet can advance to the “Milestone C” point, at which it can enter full-rate production....

...The configuration to be tested in IOT&E is the Block 3F, or baseline version, with all the weapons capability, electronic warfare, software, self-protection, maintenance, and other capabilities promised for the first all-up models. Development of Block IV upgrades, which will be back-fitted to earlier jets and be incorporated into the future production line, are already being mapped out....

...“The start of formal operational testing is a milestone more than 18 years in the making,” Program Executive Officer Vice Adm. Mat Winter said in a press statement. “It is the culmination of years of hard work and dedication from the government and industry team who completed the most comprehensive, rigorous, and … safest developmental flight test program in aviation history.” Even while IOT&E is underway, the JPO “will continue to support the delivery of phased capability improvements and modernization of the air system...."

"WASHINGTON — The F-35 has officially entered into its operation test phase, paving the way for a full rate production decision next year, the program office announced Dec. 6....

... in October, the program office temporarily put a stop to F-35 operations to conduct fuel tube inspections in the wake of an F-35B crash. Most jets were returned to flight within days after maintainers confirmed that tubes were not faulty, but aircraft with suspect tubes needed to have replacements installed. At the time, the JPO expressed confidence that it could still begin IOT&E in November.

However, 17 of the 23 aircraft picked for IOT&E flight tests were found to have faulty tubes, stated a JOTT memo obtained Defense News. That factor — along with a separate round of inspections that were authorized for some jets later in October — may have contributed to the program missing its revised start date on Nov. 13. Even with schedule delay of almost three months, the Pentagon’s current goal is to finish IOT&E by the end of summer 2019. However, a September 2018 presentation by F-35 test director Air Force Col. Varun Puri states that the test period could run into September 2019....

"F-35 Lightning II program reached another major program milestone with the official start of formal F-35 InitialOperational Test and Evaluation (IOT&E) this week. Starting this week and continuing through late summer 2019 all three F-35 Air System variants (A/B/C) will be field tested, under realistic combat conditions, for the purposes of determining the weapons systems’ operational effectiveness and operational suitability for combat.

IOT&E is designed to fully evaluate the complete air system as well as identify technical and operational areas for improvement. The independent Director of Operational Test and Evaluation (DOT&E) and Joint Strike Fighter Operational Test Team (JOTT) will execute IOT&E with our U.S. Services, United Kingdom, Dutch and Australian partners participating. All test events will be conducted at U.S. Military testing ranges and installations. Following the evaluation, the Department will have the required data to share with our Partners and to inform our “Milestone C” acquisition decision, leading to formal entry into full rate production at the end of 2019.

“The start of formal operational testing is a significant milestone for our entire F-35 Enterprise,” said Vice Adm. Mat Winter, F-35 Program Executive Officer. “It is the culmination of years of technical, programmatic and operational work and dedication from our joint government and industry team. I am extremely proud of our team’s commitment to testing excellence and dedication to providing our warfighter affordable, effective capabilities for mission success.”

"The Air Force’s initial operational test and evaluation process for the F-35 kicked off with a Dec. 5 large force employment flight of seven aircraft flying different mission types at Edwards AFB, Calif.

The 31st Test and Evaluation Squadron at Edwards has 10 pilots, 145 maintainers, and 11 engineers working on the program, alongside Lockheed Martin and the F-35 Joint Program Office, according to an Edwards release.

During the first flight, the seven aircraft flew offensive counter air, suppression of enemy air defenses, and air attack operations aimed at determining “the effectiveness and suitability for the warfighter,” Lt. Col. Nicholas Ihde, commander of the 31st TES, said in the release. The Air Force hopes to finish IOT&E in late summer.​

The Pentagon’s Prize Fighter Is Ready For Its Close-Up28 Dec 2018 Jamie McInyre

"...Washington Examiner: Your office announced in December that the F-35 is ready for its close-up, in a sense, with the start of the Initial Operational Test and Evaluation phases, known in Pentagonese as “IOT&E.” Why is this such an important milestone?Winter: Every program is required to have an independent operational evaluation to ensure the weapon system meets the required effectiveness and suitability that the war fighter needs to fight the fight, win, and come home safe. The F-35 is no different. The outcome of IOT&E is an assessment of that effectiveness and suitability, so that we can tell Congress the taxpayer dollars that were invested provided the capability that our war fighters needed. It's a very significant milestone for every program, including the F-35, and we're excited that we formally kicked off Dec. 5, and it will go through September of this year....

…Washington Examiner: Arizona Rep. Martha McSally has been appointed to serve out the rest of the late Sen. John McCain’s term, and you know what that means. McSally, a former A-10 squadron commander, is a fierce advocate of the A-10’s ability to support troops on the ground. She’s going to want to know if the F-35 can really outperform the A-10 in a close air support mission.Winter: First of all, I want to congratulate Sen. McSally on her appointment, and we look forward to working with her and her staff as well as the rest of our congressional colleagues in executing our F-35 enterprise mission. On the A-10/F-35 comparison tasking, the department’s Director of Operational Test will assess the data being collected as part of the formal operational test execution and provide that assessment to Congress as well as to the Defense Department as part of the formal evaluation reporting process later in 2019.

...Washington Examiner: The outgoing [now former] Defense Secretary Jim Mattis set a goal of a mission capable rate of 80 percent for front line combat planes like the F-35. He won’t be around to hold you to that, but can a new aircraft like the F-35 meet such an ambitious goal?Winter: The answer is yes, but as my previous response indicates, this is a tough challenge. Our approach is to break down the current 350-plus jets that are delivered into three categories. The first is “combat coded.” Those are the ones our U.S. services and our Israeli teammates are fighting with right now. The second category is training aircraft, aircraft that are dedicated to train pilots. The third category is test aircraft.

The "mission capable" definition indicates that the aircraft is available and can execute one or more of its assigned missions when the war fighter needs it. Right now, our combat-coded aircraft are experiencing effective MC rates but are not meeting the SECDEF’s mandate yet. We have identified the enablers to increase our MC rates, with the need for available spare parts as the biggest factor...."